Field of the Invention
The proposed group of inventions relates to methods for depositing luminescent coatings on the screens, using which an image is detected and/or converted, in particular, to methods of forming a structured scintillator on the surface of a photodetector intended for detection of X-ray or gamma radiation, hereinafter referred to as the detected radiation, as well as to devices for obtaining an X-ray image or an image obtained by detection of gamma radiation, particularly to devices for X-ray mammography and tomosynthesis.
Description of Related Art
So-called “flat” visible image detectors, including those for mammography, which performs the conversion of X-ray image (“shadow”) of the test subject to the electrical signals, are used to construct digital X-ray detectors. These flat detectors are full-dimensional (array) image sensors with a spatial conversion scale of 1:1.
The photodetector itself has a high sensitivity in the range of wavelengths of visible light (between about 400 and 700 nm), but usually it is X-ray insensitive. Accordingly, the X-ray phosphor coatings or so-called scintillation screens (scintillators) having different conversion efficiencies and scattering characteristics are used to convert an X-ray image into a visible image. This screen is physically placed (docked) onto the photodetector, thus forming an “image-to-electrical signal” transformation stack. The signal, in turn, is converted to digital form and transmitted to the processing and rendering.
The essential problem of the “screen-photodetector” stack is an optical scattering provokes the partial exposure of image areas (pixels) by the light from adjacent areas. The level of such stray light is defined by factors such as:                directional characteristics of the screen luminosity (aperture);        distance between the surfaces of the screen and photo detector in the stack.Also, an additional reduction in the contrast is caused by internal re-reflections in the scintillator (screen).        
An accurate alignment of the array photodetector structure with a scintillator structure divided into pixel areas of the screen is one of the main technically complicated and technologically time-consuming tasks. The equipment needed for the purpose of such an alignment and the value of its depreciation significantly increase the cost of the product built on structured phosphor.
In addition, the formation of special partitions in the scintillator is an expensive and extremely high-tech process that requires the use of expensive equipment and skilled personnel.
The prior art contains, a detector that has a structured scintillator and a method for depositing the said scintillator on the surface of the photodetector using the silk-screen printing method are known (JP2002-139568, CANON KK, G01T1/20, publ. 17.05.02, prototype). The disadvantage of this method is that it requires prior manufacture of a grid consistent with the size of the pixels of the photodetector and therefore a precise alignment procedure during the process of phosphor deposition. This invention actually limits the minimal size of a pixel to be deposited to the photodetector to 150-200 microns corresponding to the limitation of resolution of the silk-screen process. In general, the printing methods described in the said patent, are so-called integral ones, i.e. aimed to obtain a structural array of the scintillator in a single cycle without the possibility of formation of each (or a single) element of the structure separately.